This invention relates, generally, to containers in which stacks of sheets are stored, and more particularly, it relates to an apparatus for automatically maintaining pressure at certain locations on the rear of a stack of sheets so as to facilitate the dispensing of sheets via pickers, for example, at the front end of the stack.
The cash dispensing machines or Automated Teller Machines (ATMs) in use today, generally use containers or currency cassettes in which stacks of currency are stored. Generally, one cassette holds a stack of one denomination of currency. When the cassette is installed in an ATM, its dispensing end is positioned therein to enable a "picker mechanism" in the ATM to "pick" the front sheet or bill from the stack of bills in the cassette as part of a cash dispensing operation. Most cassettes have a simple pusher plate located therein which is used to resiliently bias the stack of sheets towards the dispensing end of the cassette as bills are picked from the stack in normal cash dispensing operations by the ATM. The cassettes are also used in Teller Assist Currency Dispensers (TACD) which facilitate the counting of currency to be dispensed by human tellers.
One of the problems which develops with cassettes of the type mentioned in the previous paragraph is that of "wedging". The wedging problem is due, basically, to the way in which currencies are made. For example, when a particular bill or note is embossed or printed, the embossing or printing may be heavier or more pronounced on one side or end of the note than on the other side or end. Although the variation or increase in thickness is slight for one bill or note, the variations accumulate rapidly when several hundred such bills are formed into a stack in the cassette. This results in the "wedging" problem mentioned (as shown in FIG. 1), in that one side, for example, of the rear of the stack is not pushed towards the dispensing end of the cassette by the associated pusher plate.
This wedging problem is not predictable in any way; it varies with the currency of one country, with currency denominations, and even with new and old currency of that country. Some foreign currencies also experience severe wedging problems in more than one direction when stacked in a cassette; this is due, generally, to the currency having more than one thick area on the bill.
One current method of solving the wedging problem mentioned is to alternate the orientation of the notes or bills as they are formed into a stack in the cassette. This method makes loading the cassettes more difficult and time consuming than loading without regard to orientation. If the process of alternating the orientation of the notes is forgotten, or done incorrectly, serious problems are created when a cassette, so loaded, is placed in an ATM, for example, because the "picker mechanism" associated with the ATM will fail to "pick" the bills from the cassette.